1. Field of the Invention
The present invention relates to a device capable of detecting vibration/shock, and more particularly, to a device capable of detecting vibration/shock integrated with a laser diode or a photo detector chip within a pick-up head.
2. Description of the Prior Art
Generally speaking, a vibration or shock usually causes an optical disk drive to read data from a disk in error or to write data to a disk in error, and sometimes results in break down of the pick-up head of the optical disk drive and/or damage to the disk.
For protecting the optical disk drive and the disk from being damaged by vibration or shock, there must be some mechanism for detecting any significant vibration and shock in the disk drive. In an optical disk drive, the tracking error signal may be utilized to detect vibration and shock; when an optical disk drive suffers from vibration or shock, the steady state error of the tracking error signal increases. Due to this phenomenon, the tracking error signal can be utilized to determine the magnitude of the vibration/shock suffered by the optical disk drive. Correspondingly, the disk drive initiates a reduction in rotational speed or even shuts down when significant vibration/shock is detected to prevent the further damage.
However, the conventional method of determining the magnitude of vibration/shock by monitoring the tracking error signal is not instantaneous. That is, when the vibration/shock is detected, usually the damage has already occurred, which means any errors in reading or writing data have been made already.
Moreover, sometimes the vibration/shock is not reflected by the tracking error signal, or the tracking error signal does not result from vibration/shock suffered by the optical disk drive. Therefore, it is a drawback of the conventional method of determining the magnitude of vibration/shock by utilizing the tracking error signal that erroneous determination is possible, hence the efficiency and accuracy of reading and writing of the optical disk drive is reduced.